Electronic plural component proportioner

ABSTRACT

An electronic apparatus is provided for dispensing plural component materials having first and second (and optionally third) components and a desired ratio between the components. The apparatus has first and second reciprocating pumps ( 4 ), each of the pumps ( 4 ) being connected to a source of one of said components, first and second reciprocating drivers ( 5 ), each driver ( 5 ) being connected to drive one of the pumps and forming a driver-pump set, a position sensor ( 6 ) attached to each driver-pump set, each position sensor ( 6 ) outputting increments of resolution corresponding to a fixed volume being pumped by the driver-pump set to which it is connected, and a controller attached to the drivers and the position sensors to alternately move one of the driver-pump sets one said increment and the other of the driver-pump sets the product of one increment and the ratio.

RELATED APPLICATION

[0001] Provisional U.S. Application serial No. 60/186405, filed Mar. 2,2000.

TECHNICAL FIELD

[0002] Mixing and dispensing apparatus for plural component materials.

BACKGROUND ART

[0003] As plural component materials such as paints and the like havebecome more popular and widespread in recent years, there has been anincreasing desire on the part of users of such materials for bettersolutions to mix and dispense those materials. The traditional lowtechnology way of using such materials is commonly known as hot potting.In hot potting, the user merely pours the desired amounts of the two (ormore recently three) components into a container, mixes them and thensprays or otherwise applies the material to a substrate. In addition tothe mess involved in doing so, such use often results in inaccuratemixing and wasted material as often the total amount of material mixedis not utilized.

[0004] Mechanical proportioners such as Graco's HYDRA-CAT® are suitablein such applications yet provide no monitoring functions and often lackflexibility in the ratios and the types of material that can be meteredand applied. Electronic proportioners have become more popular in recentyears but tend to be relatively more expensive due to the expensivefluid meters involved.

DISCLOSURE OF THE INVENTION

[0005] It is therefore an object of this invention to provide anelectronic proportioner which may be produced relatively inexpensivelyand is more suited for lower end applications and yet which providesaccurate metering and the ability to dispense two or three componentmaterials with ratio assurance.

[0006] The invention is designed as a complete package to pump,pressurize, proportion, and dispense plural component paints and othermaterials. Individual material components (typically resin, catalyst andreducer also often referred to as components A, B and C) are supplied tosimple reciprocating piston pumps through siphon hoses. The operation ofthe piston pumps are electronically and pneumatically controlled topressurize and provide flow of the materials at the selected ratiothrough hoses attached to a mix manifold fluid pressure regulator. Thematerials combine at the mix manifold and pass through a length of hoseto integrate the materials. A static mixer is used to thoroughlyintegrate and mix the materials. The mixed material is then dispensedfrom a spray gun and on to the substrate to be painted or coated. In thepreferred embodiment, the package can supply from one to threeindividual components at ratios from 1:1(:1) to 8:1(:1). In situationswhere only one or two components will de dispensed, the control for theunused component(s) is(are) set to zero. The device also allows the userto dispense single and plural component paints on ratio and on demandwithout premixing the materials which significantly reduces the amountof wasted material.

[0007] The advantage of this design over existing designs of similarcost stem from the fact that the pumps are physically independent butelectronically synchronized thus the ratios can cover a large rangewithout any change in hardware. Fixed ratio mechanical proportionersrequire different size pumps to change ratio and variable ratiomechanical proportioners have a small range of ratio that can beachieved without replacing the pumps with different sized lowers. Aratio change procedure is slow because it involves a repetitive changeand check procedure to get the ratio set to the target value. In theinstant invention, the pumps can be run independently for actions suchas flushing and priming. A mechanical proportioner with a ratio of 8:1would typically waste 8 gallons of base to prime the catalyst pump andhoses. The electronic controller offers the capability of monitoring,shutting down, and giving the user a specific code if an error occurs.Such detectable errors can include pump over-travel (off ratio),position sensor failure, pump over-speed, ratio change during run orbatch dispense, attempt to run when the ratio is set to zero and memoryfailure.

[0008] These and other objects and advantages of the invention willappear more fully from the following description made in conjunctionwith the accompanying drawings wherein like reference characters referto the same or similar parts throughout the several views.

BRIEF DESCRIPTION OF DRAWINGS

[0009]FIG. 1 is a rear view of the proportioner of the instantinvention.

[0010]FIG. 2 is a front view of the proportioner of the instantinvention.

[0011]FIG. 3 is a view of the control panel of the instant invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The instant invention as shown in FIGS. 1 and 2 is generallycomprised of a stand 1 having air controls 2 mounted thereon. Siphonhoses 3 are used to supply materials to the pumps from containers suchas the bucket shown (but not numbered). Siphon tubes 3 are attached tothe inlet of positive displacement reciprocating piston pumps 4 such asthose manufactured by Graco Inc., the assignee of the instant invention.

[0013] Piston pumps 4 are powered by double acting air cylinders 5 ofthe type commonly known and manufactured by a variety of producers suchas Bimba or American. Movement of the double acting air cylinders issensed by pump position sensors 6. Sensors 6 are preferablymagneto-restrictive position sensors such as those manufactured by MTSSystems Corporation.

[0014] The system is provided with a power assembly 8 comprised of acord, power supply and intrinsically safe barrier. Electronic controller9 is used to select the ratio. The three ratio select knobs 10 are usedto select the ratio with a zero selection turning off that component orsource. A ratio lock-out key 11 allows the user, or often the supervisorof the individual using the unit, to lock in a ratio preventinginadvertent or undesired adjustment of the ratio away from the desiredsetting. Pump independent function 12 allows running each individualpump in order to prime and flush out the system and for performingdiagnostics. Pump test function 13 runs each individual pump to dispenseequal amounts of fluid from the sample valves to verify the mechanicalpump systems are performing properly. Batch dispense function 14 runseach individual pump to dispense a fixed total amount of fluid from thesample valves at the desired ratio. An example for use of this functionmight be that while normal production takes place by spraying from aspray gun 25 directly as shown in the drawings, touch-up work might beperformed using a cup gun and the batch dispense allows dispensing of asmall amount of fluid which can be used in the cup of the gun fortouch-up work.

[0015] Run button 15 continuously runs the pumps in a sequential mannerto dispense the materials at the selected ratio. Stop button 16 stopsany function currently in operation. Error light 17 flashes a red lightwith a specific code when the controller detects an error. Power light18 on the power supply indicates when power is supplied to thecontroller. Three-way fluid valves 19 allow directing fluid to the gunor to sampling orifices. Fluid sampling orifices 20 are provided forcollecting samples. Air and fluid hoses 21 perform their respectivefunctions (air is supplied to the double acting air cylinders while thefluid carries individual material components to the mix manifold 22having an integral pressure regulator). Integrator hose 23 helps mix thematerial after the mix manifold in conjunction with typical staticmixers 24 at the beginning and end of integrator hose 23 which is inturn connected to the inlet of a spray gun 25. (Air hose 21 alsoprovides air to spray gun 25)

[0016] In operation, the components are dispensed sequentially similarto the system utilizing Graco's PRECISIONMIX product and describedgenerally in European Patent Number EP0116879. If a two componentmaterial is being dispensed at 3:1, the “A” pump would dispense threeincrements (in the preferred embodiment an increment represents 0.1inches of stroke travel for a dispense volume of 0.4526 cc) then oneincrement of “B” is dispensed and then the cycle repeats.

[0017] This system is designed so that the components of the mixedratios must be integers so that if for instance a manufacture specifiesa 2½:1 ratio, the user would select 5:2 on the control panel. Similarlyfor a three component material at, for example, 3:1:1, the “A” pumpwould dispense three increments, the “B” pump one increment, and the “C”pump one increment with the process thence repeating.

[0018] It is contemplated that various changes and modifications may bemade to the proportioner without departing from the spirit and scope ofthe invention as defined by the following claims.

1. An apparatus for dispensing plural component materials having atleast first and second components and a desired ratio between saidcomponents, said apparatus comprising: first and second reciprocatingpumps, each of said pumps having a stroke and being connected to one ofsaid components; first and second reciprocating drivers, each driverbeing connected to drive one of said pumps and forming a driver-pumpset; a position sensor attached to each said driver-pump set, each saidposition sensor outputting increments of resolution corresponding to afixed volume being pumped by the driver-pump set to which it isconnected; and a controller attached to said drivers and said positionsensors to alternately move one of said driver-pump sets one saidincrement and the other of said driver-pump sets the product of oneincrement and said ratio.
 2. The apparatus for dispensing pluralcomponent materials of claim 1 wherein said position sensors aremagneto-restrictive.
 3. The apparatus for dispensing plural componentmaterials of claim 1 wherein said resolution increments aresubstantially less than said stroke.